Hi @SteelPe ,
I would tend to agree with @EngineeringEric in most cases, the exception being if you are talking about very high internal pressures. Negative external pressure governs most cladding load calculations so it is conservative to assume that the internal depressurisation is inactive...
Hi T_Bat. The 700sq ft cutoff is significant because the gusts in the atmosphere which generate loads on the building have a specific physical size. Small elements of cladding and roofing will be fully engulfed in the strongest local gusts, so you cannot apply the MWFRS provisions but should...
Yes this provision is allowing for the fact that the peak wind load will not affect the whole roof at any one time or for the same wind direction so any structural element which supports large areas of roofing can be designed assuming a lower load averaged over the whole area.
Wind Engineer...
